1. Field of the Invention
The present invention relates generally to bus interfaces, and more specifically, to a method and system for ameliorating the effects of noise generated by interface bus drivers.
2. Background of the Invention
In low noise applications such as analog-to-digital (ADC) and digital-to-analog (DAC) converters, as well as in other mixed-signal device, the noise generated by exporting data over a bus can contribute significantly to the converter noise. In particular, in applications where a bus interface has an inherently low impedance for conducting data over large distances or where the bus impedance is low due to loading, significant switching transients are generated in the power supply distribution paths and via parasitic coupling mechanisms that affect the performance of the analog conversion circuits and other elements such as analog amplifiers in the input or output paths of the converters.
One mechanism that reduces the effects of such transient-generated noise is the use of differential interface pairs with matched impedance characteristics. Since transients are generated in both directions at each transition, the energy contributed by the transitions can be made to have a substantially zero DC value. However, the AC effects generated by the interface transitions have particular harmonic components that still effect the operation of converters and other circuits.
Therefore, it would be desirable to provide a method and apparatus that ameliorate the effects of transient noise generated by a bus interface on other circuits. It would further be desirable to provide such a method and apparatus that can be packaged in an integrated circuit containing converters or other sensitive circuits. It would also be desirable to provide such an integrated circuit requiring no additional terminals.